Basil downy mildew

To all individuals cultivating herbs, Basil, a prominent herb cultivated in Kenya, faces vulnerability to fungal pathogens such as peronospora belbahril. This pathogen can affect both culinary and ornamental varieties of basil. Basil downy mildew can inflict damage on the leaves, stems, and branches of various basil types.

The spores of this pathogen are commonly spread through wind and water splashes. Germination of spores predominantly occurs during nighttime on moist leaves, at temperatures ranging from 41 to 83°F, taking approximately two hours, after which they swiftly infect the plant tissue within a span of four hours.


The primary indication of infection is the curling and yellowing of leaves on the upper surface, which is limited to the veins and eventually leads to leaf death. Sporulation is predominantly observable in wet or humid conditions and when the leaves remain wet for extended periods. On the underside of the leaves, the sporulation typically appears as a purplish-brown to grey discoloration.

Management practices

Cultural control

  1. Adequate spacing should be maintained to ensure sufficient air circulation.
  2. It is advisable to minimize the use of overhead irrigation during conditions that are conducive to downy mildew.
  3. Employing fans can help in reducing humidity levels inside greenhouses.
  4. Consider planting basil varieties that are resistant or tolerant to downy mildew.

Chemical control

  1. Biodistinction: Apply at a rate of 1 liter per hectare.
  2. Greenphite: Apply at a rate of 4 liters per hectare.
  3. Bouncer gold: Apply at a rate of 6 liters per hectare.
  4. Chancetyl elite 800WDG: Apply at a rate of 3 kilograms per hectare.

Chancetyl Elite® 800WDG is a highly effective systemic fungicide offering broad-spectrum protection against a wide range of diseases in various agricultural crops. It possesses both preventive and curative properties, making it ideal for combating Downy mildew on Roses, Capsicum, Squash, Cabbages, and Snow peas, as well as Ring spots on Carnations and Damping off on French beans.


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